germinating acorns?

Hey, Grant. I remember you from the PFI listserv... good times. Anyway, I was wondering about oak trees and germinating acorns. Two questions:
1: What is the most effective method you've used for germinating acorns?
2: Which oak species do you find to be the most cold tolerant?

Ben Johansen wrote:Hey, Grant. I remember you from the PFI listserv... good times. Anyway, I was wondering about oak trees and germinating acorns. Two questions:
1: What is the most effective method you've used for germinating acorns?
2: Which oak species do you find to be the most cold tolerant?

1) drop the acorns into a large container of water. Compost the acorns that float to the top, this indicates that the embryo has not fully developed or is damaged, and the seed is hollow.

white oaks: don't have a dormancy. You can plant right away or keep in the fridge in moist sand over the winter and plant in spring.
red oaks: DO have dormancy. They need 4-8 weeds cold stratification - so definitely plant right away unless you can keep them at a controlled temp in moist sand in fridge.

Permies direct plant as much as possible!

2) Cold tolerant oaks: I live in zone 5, so I can only speak to the 20+ species of oak that grow here in Iowa.

Awesome. Thank you.
Dyou have any experience germinating burr oak?

Ben Johansen wrote:Awesome. Thank you.
Dyou have any experience germinating burr oak?

I've never grown bur oak before beyond enjoying the ones I see naturally germinating. i think the squirrels do all the work, but I've never paid them. I need to get more squirrels.

There's a good chance that many of them are germinating when you collect them. I'd guesss a third of the ones I sent to Ben Falk were already. They are a tour of white oak so like Grant said, shouldn't need stratification. I saved a few for for my yard but the rabbits got them. I plan to transplant some seedlings this fall or collect when dormant and plant in the spring. They'll go under my ash trees as replacements.

So is there a way to get population studies on rabbits from the DNR? That chapter in A Sand County Almanac talks about how oak tree seedling survival rates are directly proportional to the rabbit population, and I have an inkling that it would be good to try and synch up with that...

I poked half a dozen burr oak acorns into various pots last fall and ignored them all winter. Only one seems to have germinated, but it's flourishing in a small pot and I'll be planting it out in another month or so.

Hi Ben, I doubt that information is available online but if you found the right biologist they could be willing to share. Localized populations would vary significantly though...
The tree tubes of Grant's should work, even cut in half to double them would be adequate unless you also have deer pressure. I didn't protect mine at all even knowing I needed to with all the rabbits hanging around...

Jeff Reiland wrote:Hi Ben, I doubt that information is available online but if you found the right biologist they could be willing to share. Localized populations would vary significantly though...
The tree tubes of Grant's should work, even cut in half to double them would be adequate unless you also have deer pressure. I didn't protect mine at all even knowing I needed to with all the rabbits hanging around...

"But I know from the history of present seedlings that no oak grows above the reach of rabbits without a decade or more of getting girdled each winter, and re-sprouting during the following summer. Indeed, it is all too clear that every surviving oak is the product either of rabbit negligence or of rabbit scarcity. Some day some patient botanist will draw a frequency curve of oak birth years, and show that the curve humps every ten years, each hump originating from a low in the ten year rabbit cycle. (A fauna and flora, by this very process of perpetual battle within and among species, achieve collective immortality.)"
Aldo Leopold, A Sand County Almanac

Granted, its just a theory, but one that I think deserves investigation- stumping any plant causes roots to beef up production, so's they can grow the top back. Maybe stumping or heavy pruning seedlings results in better plant vigor? I mean, there's something to be said for happy, unstressed plants, but sometimes, zat vich does not kill us makes us stronger, ja? I mean, the first red delicious apple tree was cut off below the meristem many times, and it grew back with greater and greater vigor each time, until its owner decided to let it grow (bad example; red delicious=junkmush.) Has anybody tried pruning em heavy in the fall? Maybe even stumping?

Ben Johansen wrote: Maybe stumping or heavy pruning seedlings results in better plant vigor?

I have a theory on this too...

Seasonal and repeated nibbling, pruning, trampling, or winterkill of topgrowth may encourage directed growth of root mass. Eventually, there is enough root mass to drive 5-6' of growth in a single season - which permanently puts the apical meristem above browse height.

I've seen this with apples, persimmon, walnut, and black locust.

Perhaps it's confirmation bias, but nature is a clever girl.